The present invention relates in general to shredders, and in particular to a shredder which produces a downdraft effect when shredding the material which is supplied to the top of the shredder.
Shredders are pieces of equipment used in a variety of industries with numerous designs to suit different applications. Typically, a shredder consists of an enclosed rotor with any number of hammers attached to the rotor by means of hammer pins. The rotor is spun at a high speed by either an electric motor or a diesel engine. When material is fed into the shredder, impact is made with the feed material by the heavy high speed hammers, resulting in the reduction in particle size of the feed material. Grate bars are located directly beneath the spinning hammers and are designed to cause impact with the material being shredded by the hammers and to control the desired particle size of the shredded material. The larger the grate openings, the larger the particle size.
Most shredders produce an updraft of air and particles blowing back up the inlet in an undesired manner as a result of the draft set up by the rapidly spinning hammers, and because of the dynamics of the falling material being supplied to the shredder. The preferred shredder would be one which produces a natural downdraft effect thereby drawing air as well as the feed material into the shredder inlet and into engagement with the rotating hammers.
Most shredder manufacturers claim to have the technology to construct a single direction downdraft shredder. However, once constructed, installed and operational, many of these shredders are actually updraft rather than downdraft shredders. The inventors are not aware of any known technology which would enable one to convert an existing updraft single direction shredder to a downdraft shredder.